The present invention relates to a method and apparatus for performing a charging limit control in a switched telecommunication network so as to ensure that an agreed charging limit will not be exceeded within a predetermined time period.
In general, known methods and apparatuses for pre-payment of telecommunication connections between first and second telecommunication devices involve storing monetary value data representative of a prepaid, e.g. deposited in a centralized storage device, amount of monetary value available for payment of telecommunication connections in the telecommunication switching network.
At the initiation of the first telecommunication device, a telecommunication connection is established between the first and second telecommunication devices so that a telecommunication process can be conducted therebetween. The telecommunication connection between the first and second telecommunication devices is terminated in response to a termination of the telecommunication process. The time duration of the telecommunication connection is measured. The cost of the telecommunication connection is computed using the measured time duration and applicable prepaid rate data. The stored monetary value data is processed to indicate a decrement in the available prepaid monetary value, which decrement is essentially equal to the computed cost of the telecommunication connection.
The U.S. Pat. No. 5,353,335 discloses a prepaid telephone system provided in a public switched telephone network, wherein a telephone user buys a predetermined amount of a service beforehand and receives a card imprinted with a unique account number. A plurality of tall free access telephone numbers allows the user to access the prepaid telephone system. Each of those telephone numbers causes the prepaid system to interact with the user. The user is prompted to enter his or her card number. The authenticity of the number and the available credit is determined.
If there is a certain minimum amount of credit available, the user is prompted to enter the phone number of a desired party. If the user has enough available credit to pay for at least a minimal amount of calling time, the call is completed. A timer is set with an amount of calling time permitted by the available balance. The timer runs during the course of the phone call and the call is disconnected when the timer runs out. If the call is ended prior to the timer running out, a new available balance is computed in the light of the time remaining on the timer. The user can make additional phone calls using the new available credit balance.
Furthermore, a prepaid telecommunication service is described in the U.S. Pat. No. 5,677,945, wherein credit or debit cards are used in a telecommunication network including a central data base. The system monitors card balances while blocking multiple use of card balances and sends warning messages to subscribers on card balances which approach a threshold amount. Upon initiation of a telephone call, a subscriber card balance corresponding to the subscriber""s credit or debit account is retrieved from the central data base. A switching station monitors the telephone call and initiates an alarm when the call time approaches a threshold amount specified for the card balance. The system announces to the subscriber and/or blocks the termination of the call when the threshold amount has been exceeded and a further limit specified for the card balance has been reached.
Thus, according to the known prepaid systems, one subscriber has only one charging limit, or the limit is service-specific if the subscriber has no own limit.
Moreover, several different implementations are required if existing methods of handling a subscriber data are used for achieving a flexible subscriber-based charging limit.
It is an object of the present invention to provide a simple method and apparatus for performing charging limit control, which can be adapted to different charging limit values of different calls.
This object is achieved by a method for performing charging limit control in a telecommunication switching network, comprising the steps of:
providing a charging limit file comprising a plurality of subscriber-specific charging limit records;
setting a subscriber-specific charging limit by writing limit date to the charging limit file; and
using a record index for accessing the subscriber-specific charge limit during a call.
Furthermore, the above object is achieved by an apparatus for performing charging limit control in a telecommunication switching network, comprising:
storing means for storing a charging limit file comprising a plurality of subscriber-specific charging limit records; and control means for setting a subscriber-specific charging limit by writing limit data to the charging limit file,
wherein said control means is arranged to access the subscriber-specific charging limit during a call by using a record index.
Since a charging limit file is provided comprising subscriber-specific charging limit records accessed by record indices, the charging limit control is easily adaptable to different charging limit values of different call types, by writing corresponding charging limit values into the charging limit file and storing corresponding record indices in subscriber data files. Moreover, different accesses like direct subscribers, private branch exchanges and indirect subscribers can use the same method, since the charging limit file can be centrally accessed.
Accordingly, end users are able to define a desired upper billing limit for a predetermined time period, e.g. one month, which has to be ensured by the network operator.
Since, therefore, limit counting and checking can be performed centrally, specific limit counters for each subscriber data are no longer required.
Preferably, the subscriber-specific charging limit record may comprise a plurality of subrecords, each including information about an initial limit value, a remaining value and a next time when the remaining value should be initialized to the initial value, wherein the subrecords are used for charging limits of different call types and are accessed on the basis of subscriber data.
The provision of a plurality of subrecords within each subscriber-specific charging limit record provides the advantage that own charging limits can be allocated to different call types and can be accesses by providing a corresponding index in the subscriber data. Thus, a flexible charging limit control can be established.
The subrecords comprising different charging limit values preferably can be accessed in dependence on a destination information provided in the subscriber data. Thus, the charging limit can be chosen with regard to the destination of the call, so that different charging limits can be defined for different services.
Moreover, one of the subrecords can be used as a default limit value, wherein the default limit value is used for calls which do not have own charging limits. Thereby, the default limit value can be used, in case a destination having a specific charging limit has been chosen by a subscriber having only a default limit in use.
The updating of the initial value preferably can be performed in such a way that every time the remaining value is read, the next initialization time is checked, wherein the remaining value is set to the initial value and the next time to initialize is set, when the initialization time has been achieved. Thereby, the initial value does not have to be updated for all subscribers at the same time, so that the update load of the apparatus can be decreased.
Preferably, the control means may comprise a call control means of a switching system. Thereby, a switch-based charging limit control can be performed, which may also be implemented by small operators who do not have access to an expensive IN-based prepaid service. Moreover, in known IN-based prepaid-services, one subscriber has only one charging limit, or the limit is service-specific, so that the charging limit is always the same and cannot be adapted to specific destinations of a call.
Further preferred developments of the present invention are defined in the dependent claims.